Mineral oil composition



Patented Aug. 8, 1944 MINERAL OIL COMPOSITION Darwin E. Badertscher,Woodbury, N. .L, assignor to Socony-Vacuum Oil Company, Incorporated, acorporation of New York No Drawing. Application June 11, 1943, SerialNo. 490,479

(01. asa -51) 13 Claims.

This invention has to do with the stabilization of mineral oil fractionsand more particularly has to do with the stabilization of such fractionsby the incorporation therein of a small amount of a novel compound, ornovel class of compounds, capable of inhibiting a viscous mineral oilagainst the deleterious efiects of oxidation.

It is well known to those familiar with the art that the deleteriouseffects of oxidation upon a mineral oil fraction manifests itself invarious ways depending upon the source of the oil, that is, the crudefrom which it is derived, the refining treatment to which the 'oil hasbeen subjected and the particular conditions under which the oil issubjected to oxidation. For example, mineral oil fractions refined foruse as lubricants have a tendency to oxidize under conditions of I usewith the formation of sludge or acidic oxidation products. Also, in thecase of internal combustion engines, particularly those operating withhigh cylinder pressures, there is a'decided tendency for the ordinarylubricating oil fractions to form carbonaceous deposits which cause thepistonrings to become stuck in their slots and which fills the slots inthe oil ring or rings, thus materially reducing the efficiency of theengine.

Among the numerous improving agents proposed for use in mineral oilfractions are various metal salts and metallo-organic compounds.

solubility in non-associated solvents. Further distinctions betweenchelate metal salts and nonchelate metal salts may be obtained byreferring to Sidgwick's The Electronic Theory of Valence, OxfordUniversity Press, 1927, chapter 14.

The oil improving agents contemplated herein,

which effectively stabilize mineral oil fractions against thedeleterious eifects of oxidation, are the chelate metal salts of asalicylidene imlne which may be unsubstituted or substituted. Thesemetal salts may be represented by the following general' formula:

wherein R is selected from the group consisting alkoxy, aroxy, halogen,nitro, nltroso and cyano;

R is selected from the group consisting of hydrogen and hydocarbonradicals such as alkyl, aryl, alkaryl and aralkyl; and M represents thehydrogen equivalent of a metal.

All metals capable of forming chelate metal salts are contemplated,fisconstituents of the metal salts described above. Illustrative of suchmetals are: sodium, copper, beryllium, magnesium, boron, aluminum,silicon, arsenic, antimony, chromium, iron, cobalt, nickel, palladium,platinum and iridium. Particularly preferred of such metal constituentsare the metals nickel, copper and cobalt in the followingformsynlckelous, cupric and'cobaltous.

While the imino hydrogen (=N-H) may be present in the metal saltscontemplated herein,

it is preferred that the imino hydrogen be replaced by a hydrocarbonradical such, for exhigh vapor pressures in addition to increasedample,as an alkyl or an aryl radical. Radicals representative of theseclasses are butyl, dodecyl and tolyl.

quently are contemplated herein. Typical of the C-substituents arealkyl, aralkyl and alkaryi groups.

The chelate metal salts of phe-tyrsnennea Y above may be prepared by thegeneral method described in detail by Hunter and Marriott in the Journalof the Chemical Society (London) 1937, page 2000. Illustrative of thegeneral method and of the chelate metal salts prepared thereby are thefollowing examples.

E'xsurnl Nickelous salicwlidene N-n-butyl imine A hot solution of 17.5grams oi salicylaldehyde in 20 cc. of 95% ethanol was added to a hotsolu- .tion of 11 grams of mono-n-butyl amine in 20 cc. of 95% ethanol,the latter solution being constantly agitated. The reaction was stronglyexothermic and caused the mixture to boil vigorously. A hot solution of18 grams of nickelous acetate, Ni(OAc):.4I-Ia0, in 100 cc. of 50%aqueous ethanol was added to the aforesaid mixture, with constantagitation. About 44.5 gramsof alcoholic potassium hydroxide containing183% of 85% potassium hydroxide was then added. A dark green oilimmediately formed and crystallized on cooling. The olive green crystalsobtained by filtering the last mentioned mixture were washed on thefilter with distilled water, then with 50 cc. of 95% ethanol in threeportions and finally with 20 cc. of absolute ethanol. Crystallizationfrom acetone yielded dark olive green crystals melting sharply at139.5-140' C. (uncorrected); On analysis the following data wasobtained.

. Cal'd. ior Analysis Found CHnNNi 1722 P" 14 3 Ni k l Nigm mn 6.46 I6.83

EXAIPLI II Cupric salicylidene N-n-butul imine To a hot solution of 8.2grams of cupric acetate monohydrate and 6 grams of mono-butyl amine in120 cc. of 50% aqueous ethanol was added, with shaking, a solution of 10grams of salicylaldehyde in 10 cc. of 95% ethanol. After the mixture hadcooled, the dark olive green crystals formed thereon were filtered,washed in the filter first with distilled water and then with absoluteethanol-and were finally air dried. Analysis of these crystals showedthe following;

m M Cases.

Peron;8 Permit11s 4 Copper 16. Nitrogen 6.44 0.8

Exnn'm: III

Cobaltous salicyliderte N-n-butyl imine This material was prepared from25 grams of salicylaldehyde, 15 grams of mono-butyl amine and 24.5 gramsof cobaltous acetate tetrahydrate using a procedure similar to thatdescribed in Example I. The product was a crystalline, brick red solidwhich analyzed as follows:

Analysis Found gflg Pacing, Percento M n e 14. 3 16. 87

Exnrru: IV

Cobaltous salicylidene N-n-dodecyl imine A hot solution of 25 grams(excess) oisalicyl- I aldehyde in 30 cc. of absolute ethanol was addedto a hot solution of 37 grams of 'mono-n-dodecyl amine in 70 cc. of 95%ethanol, the mixture being agitated throughout the addition. Thereaction was exothermic causing the mixture to ,boil vigorously. To theresulting mixture was added a solution of grams of cobaltous acetatetetrahydrate in' a mixture of 50 cc. oi water'and 60 cc. of 95% ethanol.The light yellow imine solution immediately turned brown on additionofthe cobalt salt. After heating on the hot plate at a temperature ofabout 60 C. for about ten minutes a with I shaking, 77-78 grams of 14%alcoholic potassium hydroxide was added. The mixture now became greendue-to the separation of a dark green liquid phase. Five hundred cc. ofdistilled water were added to the reaction mixture and the resultingmixture was extracted thoroughly with petroleum ether until thepetroleum ether extracts were no longer, colored; On evaporation ofpetroleum ether from the extracts, 57.5 grams of a dark green pastyresidue were obtained. A small drop of this residue fused in a porcelaincrucible with about 2 to 3 cc. of borax gave a brilliant bluecoloration, indicating, the presence of cobalt.

To demonstrate the eflectiveness of the salts contemplated herein as oilimproving agents, a blank oil and blends of typical improving agents ofthe type contemplated herein were subjected to an oxidation test inorder to determine their relative susceptibility to oxidation. In thistest a 300 gram sample of the blank oil or of the oil blend was heatedat 350 F. while two liters of air per hour were blown over theirrespective surfaces and while stirring the samples at a constant ratewith steel paddles. The oil used was a commercial, solvent-refined S. A.E. 30 motor oil. Samples were withdrawn at specified intervals (in days)and the volume per cent of sludge was determined in each case. Theresults are set forth below in Table 1.

In order to evaluate the relative stability of a motor oil and of blendsof the same motor oil and typical improving agents of the typecontemplated herein the blank oil and the blends were tested in astandard C. I". R. knock test" en ine.

The test involved operating the engine first with the oil and then withthe oil blend at an approximate speedof 1200 R. P. M. with the throttleset Just below detonation using a compression ratio of 7:1 .at a fixedjacket temperature of 400' F.

cylidene imine, said At the end of 28 hours, the following inspectionswere made: 1. The piston:

a. Degree of ring sticking being an entirely free ring and 360 a totallystuck ring) b. Per cent of filling of oil slots 0. Deposits (grams) 2.Used oil:

a. Kinematic viscosity (K. V.) at 210 F. b. Neutralization number (N.N.)

The results obtained are listed below in Table 2 where oil A is a motoroil blank, oil B is the some oil containing 0.5 per cent of ni-ckeloussalicylidene N-n-butyl imine and oil C is the same oil containing 1 percent of nickelous salicylidene N-n-dodecylimine.

The amount of improving agents which may. be used in the oil will varymore or less with the oil and with the conditions of use. While ingeneral the desired improvement can be effected with amounts rangingfrom about 0.01 per cent to about 10 per cent, the preferred amountswill fall within the range of about 0.1 per cent to about 5 per centdepending on solubility.

It is to be understood that while we have described hereinabovepreferred procedures for synthesizing improving agents of the typecontemplated herein and have designated certain illustratlve reactantsand have also shown certain preferred mineral oil fractions which may beemployed, the invention is not confined to the specific detailedprocedural operations, reactants or oils so described but includeswithinits scope what-' ever changes fairly come within the spirit of theappended claims.

I claim:

1. An improved mineral oil composition com-. prising a viscous mineraloil having in admixture therewith a minor proportion, sufllcient tostabllize said mineral oil against the deleterous effects of oxidation,0! a chelate metal salt of a sailsalt being represented by the formulawherein R and R. are selected from the group consisting of hydrogen anda hydrocarbon radical and M is the hydrogen equivalent of a metalpossessed of the capacity to form a chelate metal 2. An improved mineraloil composition comprising a viscous mineral oil having in admixture.

therewith a minor proportion, from about 0.01 per cent to about 10 percent, of achelate metal salt of a salicylidene imine, said salt beingrepresented by the formula 1 eifects of oxidation, of a chelate metalsalt of a salicylidene imine, said salt being represented by the formulav wherein R and R are selected from the group consisting of hydrogen anda hydrocarbon radical and M is the hydrogen equivalent of a metalpossessed of the capacity to form a chelate metal salt and is selectedfrom the group consisting of copper, cobalt and nickel.

4. An improvedmineral oil composition comprising a viscous mineral oilhaving in admixture therewith a minor proportion, sufflcient tostabilize said mineral oil against the deleterious eflects of oxidation,of a chelate metal salt of a salicylidene imine, said salt beingrepresented by the formula wherein R and R are selected from thegroupconsisting of hydrogen and a hydrocarbon radical and M is the hydrogenequivalent of a metal possessed of the capacity to form a chelate metalsalt and is selected from the group consisting of copper (cupric),cobalt (cobaltous) and nickel (nickelous).

5. An improved mineral oil composition com prising a viscous'mineral oilhaving in admixture therewith a minor proportion, suflicient tostabilize said mineral oil against the deleterious effects of oxidation,of'a chelate metal salt 'of salicylidene imine.

6. An improved mineral oil composition comprising a viscous mineral oilhaving in admixture therewith a. minor proportion, suificient tostabilize said mineral oil against the deleterious efi'ects ofoxidation, of a chelate metal salt of an N-substituted' salicylideneimine 7. An improved mineral oil composition comprising a viscousmineral oil having in admixture therewith a minor proportion, sufiicientto stabilize said mineral oil against the deleterious eflects ofoxidation, oi a chelate metal salt of an N-aryl substituted salicylideneimine.

8. An improved mineral oil composition comprising a'viscous mineral oilhaving in admixture therewith a minor proportion, sufllcient tostabilize said mineral oil against the deleterious eflects oi oxidation.or a chelate metal salt oi an N-alkyl substituted salicylidene imine.

9. An improved mineral oil composition comprising a viscous mineral .oilhaving in admixture therewith a minor proportion, suilicient tostabilize said mineral oil against the deleterious eiiects of oxidation,of a chelate metal salt of a C-substltuted salicylidene imine.

10. An improved mineral oil composition comprising a viscous mineral oilhaving in admixture therewith a minor proportion, sumcient to stabilizesaid mineral oil against the deleterious eflects of oxidation, of achelate metal salt or an N-substituted, C-substituted salicylideneimine.

ture therewith a minor proportion, sumcient to stabilize said mineraloil against the deleterious eflects 0! oxidation, of cobaltoussalicylidene N-n-butyl imine.

DARWIN E. BADERTSCHER.

